Leveraging noisy side information for disentangling of factors of variation in a supervised setting

Ce mémoire est composé de trois articles et présente les résultats de travaux de recherche effectués dans le but d'améliorer les techniques actuelles permettant d'utiliser des données associées à certaines tâches dans le but d'aider à l'entraînement de réseaux de neurones sur une tâche différente. Les deux premiers articles présentent de nouveaux ensembles de données créés pour permettre une meilleure évaluation de ce type de techniques d'apprentissage machine. Le premier article introduit une suite d'ensembles de données pour la tâche de reconnaissance automatique de chiffres écrits à la main. Ces ensembles de données ont été générés à partir d'un ensemble de données déjà existant, MNIST, auquel des nouveaux facteurs de variation ont été ajoutés. Le deuxième article introduit un ensemble de données pour la tâche de reconnaissance automatique d'expressions faciales. Cet ensemble de données est composé d'images de visages qui ont été collectées automatiquement à partir du Web et ensuite étiquetées. Le troisième et dernier article présente deux nouvelles approches, dans le contexte de l'apprentissage multi-tâches, pour tirer avantage de données pour une tâche donnée afin d'améliorer les performances d'un modèle sur une tâche différente. La première approche est une généralisation des neurones Maxout récemment proposées alors que la deuxième consiste en l'application dans un contexte supervisé d'une technique permettant d'inciter des neurones à apprendre des fonctions orthogonales, à l'origine proposée pour utilisation dans un contexte semi-supervisé.The thesis is composed of three articles and presents the results of research done in order to improve the current methods for improving a neural network's performance on a given task by taking advantage of data from other tasks. The two first articles present new datasets created to allow better evaluation of this type of machine learning methods. The first article introduces a dataset suite for the task of handwritten digit recognition. This dataset suite was created from the existing dataset MNIST to which new factors of variation have been added. The second article introduces a new dataset for the task of facial expression recognition. It is composed of images of faces that were automatically collected from the Web and then labelled. The third and last article presents two new approaches to improving performance on a task of interest by leveraging labels from another task in the context of multi-task learning. The first approach is a generalization of the recently introduced Maxout Networks designed for multi-task learning. The second approach consists in the application in a fully-supervised setting of the previously introduced Contractive Discriminant Analysis penalty, originally used in the semi-supervised setting to make groups of neurons learn features orthogonal to each other

Challenges in Representation Learning: A report on three machine learning contests

The ICML 2013 Workshop on Challenges in Representation Learning focused on three challenges: the black box learning challenge, the facial expression recognition challenge, and the multimodal learning challenge. We describe the datasets created for these challenges and summarize the results of the competitions. We provide suggestions for organizers of future challenges and some comments on what kind of knowledge can be gained from machine learning competitions.Comment: 8 pages, 2 figure

Validation of the Body Concealment Scale for Scleroderma (BCSS): Replication in the Scleroderma Patient-centered Intervention Network (SPIN) Cohort

© 2016 Elsevier Ltd Body concealment is an important component of appearance distress for individuals with disfiguring conditions, including scleroderma. The objective was to replicate the validation study of the Body Concealment Scale for Scleroderma (BCSS) among 897 scleroderma patients. The factor structure of the BCSS was evaluated using confirmatory factor analysis and the Multiple-Indicator Multiple-Cause model examined differential item functioning of SWAP items for sex and age. Internal consistency reliability was assessed via Cronbach's alpha. Construct validity was assessed by comparing the BCSS with a measure of body image distress and measures of mental health and pain intensity. Results replicated the original validation study, where a bifactor model provided the best fit. The BCSS demonstrated strong internal consistency reliability and construct validity. Findings further support the BCSS as a valid measure of body concealment in scleroderma and provide new evidence that scores can be compared and combined across sexes and ages

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

L’ÉTUDE DE TRAJECTOIRES D’IMPLANTATION DE BAROMÈTRE, UN OUTIL NUMÉRIQUE VISANT À ACTUALISER L’APPROCHE DE PERSONNALISATION DES SERVICES SOCIAUX

La personnalisation des services sociaux propose une approche de plus en plus valorisée dans les pratiques. Elle vise à offrir plus de choix et de contrôle aux personnes en misant sur leurs forces pour coproduire l’intervention. Pour accompagner le changement de culture qu’exige ce type d’approche, un outil d’intervention informatisé et interactif a été développé, nommé Baromètre. Comment une technologie numérique comme Baromètre peut-elle agir comme condition sociotechnique contribuant au changement de culture? Nous avons réalisé une recherche qualitative utilisant une stratégie d’étude de cas multiples. Quatre milieux de pratique nous ont servi d’observatoires : deux organismes communautaires en santé mentale, un département de psychiatrie et un centre de formation pour adultes. Trois types de collecte de données ont été utilisés : des entretiens individuels semi-directifs auprès des usagers, des entretiens d’explicitation de la pratique auprès d’intervenants pour produire des histoires d’utilisation, des entretiens de groupe auprès d’usagers et d’intervenants. Nous avons analysé les données au moyen d’un modèle des forces croisant quatre modes opératoires d’expérimentation : généraliste, expansionniste, particulariste et déliquescent. L’analyse permet d’observer une tendance à la déliquescence des expérimentations-pilotes. Or, la déliquescence n’est pas causée par la technologie en elle-même, mais par les conditions contextuelles des expérimentations.The individualization of social services proposes an approach that is increasingly valued in practice. It aims to offer more choices and control to people by building on their strengths to co-produce intervention. To support the cultural change required by this type of approach, a digital and interactive intervention tool has been developed, called Baromètre. How can a digital technology like Baromètre act as a socio-technical condition contributing to culture change? We conducted qualitative research using a multiple case studies strategy. Observations were made in four practice settings: two community mental health organizations, a department of psychiatry and an adult education center. Three types of data collection were used: individual semi-structured interviews with service users, practice clarification interviews with practitioners to produce narratives in relation to its use, and group interviews with service users and practitioners. The data was analyzed using four operational modes of experimentation: generalist, expansionist, particularist and deliquescent. The analysis shows a tendency towards deliquescence in pilot experiments. However, the delinquescence is not caused by the technology itself, but by the contextual conditions of the experiments

La personnalisation des services de santé mentale : une voie d’avenir

La personnalisation des services de santé mentale est indissociable d’un processus qui vise à penser et à circonscrire les effets recherchés par les personnes comme des aspirations légitimes, élargissant ainsi leurs possibilités de choix et de contrôle. Dans un premier temps, nous démontrerons que cette visée de personnalisation ne peut être détachée d’un contexte général et de contextes spécifiques, qu’ils soient français, anglo-saxons, québécois ou autres. L’approche narrative constitue à cet égard un apport essentiel favorisant la prise en compte des liens de codétermination entre façons de savoir et formes de pouvoir. Par la suite, les politiques, pratiques et recherches au Royaume-Uni en regard de la personnalisation seront mises en évidence avec un accent particulier sur les approches et outils d’intervention dans le champ de la santé mentale. C’est dans ce cadre que nous présenterons le « Projet Baromètre » dont l’une des retombées est la conceptualisation d’un outil d’intervention et d’évaluation, interactif et accessible via le web, qui met en évidence les forces et les progrès de la personne dans sa communauté.Objectives: To demonstrate the pertinence of putting personalisation at the heart of mental health services.Methods: Review of littérature of personalisation research and intervention in the United Kingdom, the country where the personalisation is one of the key themes of the health and social services reform agenda.Results: Presentation of the key challenges in the personalisation agenda and also of web tool directly inspired by research and practices in the UK.Conclusion: We think that individuals want to be treated as citizens that want control and choice over their destiny

Effects of intraoperative hemodynamic management on postoperative acute kidney injury in liver transplantation: An observational cohort study.

BACKGROUND:Intraoperative restrictive fluid management strategies might improve postoperative outcomes in liver transplantation. Effects of vasopressors within any hemodynamic management strategy are unclear. METHODS:We conducted an observational cohort study on adult liver transplant recipients between July 2008 and December 2017. We measured the effect of vasopressors infused at admission in the intensive care unit (ICU) and total intraoperative fluid balance. Our primary outcome was 48-hour acute kidney injury (AKI) and our secondary outcomes were 7-day AKI, need for postoperative renal replacement therapy (RRT), time to extubation in the ICU, time to ICU discharge and survival up to 1 year. We fitted models adjusted for confounders using generalized estimating equations or survival models using robust standard errors. We reported results with 95% confidence intervals. RESULTS:We included 532 patients. Vasopressors use was not associated with 48-hour or 7-day AKI but modified the effects of fluid balance on RRT and mortality. A higher fluid balance was associated with a higher need for RRT (OR = 1.52 [1.15, 2.01], p<0.001 for interaction) and lower survival (HR = 1.71 [1.26, 2.34], p<0.01 for interaction) only among patients without vasopressors. In patients with vasopressors, higher doses of vasopressors were associated with a higher mortality (HR = 1.29 [1.13, 1.49] per 10 μg/min of norepinephrine). CONCLUSION:The presence of any vasopressor at the end of surgery was not associated with AKI or RRT. The use of vasopressors might modify the harmful association between fluid balance and other postoperative outcomes. The liberal use of vasopressors to implement a restrictive fluid management strategy deserves further investigation